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Ecological differentiation in xylem cavitation resistance is associated with stem and leaf structural traits
Author(s) -
MARKESTEIJN LARS,
POORTER LOURENS,
PAZ HORACIO,
SACK LAWREN,
BONGERS FRANS
Publication year - 2011
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2010.02231.x
Subject(s) - xylem , biology , evergreen , deciduous , cavitation , dry season , resistance (ecology) , tropical and subtropical dry broadleaf forests , ecology , phenology , dry weight , botany , physics , mechanics
Cavitation resistance is a critical determinant of drought tolerance in tropical tree species, but little is known of its association with life history strategies, particularly for seasonal dry forests, a system critically driven by variation in water availability. We analysed vulnerability curves for saplings of 13 tropical dry forest tree species differing in life history and leaf phenology. We examined how vulnerability to cavitation (P 50 ) related to dry season leaf water potentials and stem and leaf traits. P 50 ‐values ranged from −0.8 to −6.2 MPa, with pioneers on average 38% more vulnerable to cavitation than shade‐tolerants. Vulnerability to cavitation was related to structural traits conferring tissue stress vulnerability, being negatively correlated with wood density, and surprisingly maximum vessel length. Vulnerability to cavitation was negatively related to the Huber‐value and leaf dry matter content, and positively with leaf size. It was not related to SLA. We found a strong trade‐off between cavitation resistance and hydraulic efficiency. Most species in the field were operating at leaf water potentials well above their P 50 , but pioneers and deciduous species had smaller hydraulic safety margins than shade‐tolerants and evergreens. A trade‐off between hydraulic safety and efficiency underlies ecological differentiation across these tropical dry forest tree species.